Code of Federal Regulations Title 7. Agriculture § 7.1755.860—Thermal Reel Wrap Qualification

(I) The test procedures described in this appendix are for qualification of initial and subsequent changes in thermal reel wraps.

(II) Sample Selection. All testing must be performed on two 450 millimeter (18 inch) lengths of wire removed sequentially from the same 3 pair, 22 gauge jacketed wire. This wire must not have been exposed to temperatures in excess of 38°C since its initial cool down after sheathing.

(III) Test Procedure. (1) Place the two samples on an insulating material such as wood, etc.

(2) Tape thermocouples to the jackets of each sample to measure the jacket temperature.

(3) Cover one sample with the thermal reel wrap.

(4) Expose the samples to a radiant heat source capable of heating the uncovered jacket sample to a minimum of 71°C. A 600 watt photoflood lamp or an equivalent lamp having the light spectrum approximately that of the sun shall be used.

(5) The height of the lamp above the jacket shall be 380 millimeters (15 inches) or a height that produces the 71°C jacket temperature on the unwrapped sample.

(6) After the samples have stabilized at the temperature, the jacket temperatures of the samples must be recorded after one hour of exposure to the heat source.

(7) Compute the temperature difference between the jackets.

(8) For the thermal reel wrap to be acceptable to RUS, the temperature differences between the jacket with the thermal reel wrap and the jacket without the reel wrap must be greater than or equal to 17°C.